This task is to add the missing const in the test framework and test suites to reduce RAM usage.
The "static struct test_t" variables could be const all over the test suites.
Also the set_testsuite(...) function, which used to register the test suites, need to be modified to avoid compiler warning.
This task is related to this comment:
https://review.trustedfirmware.org/#/c/287/3/test/suites/attestation/non_secure/attestation_ns_interface_testsuite.c@23